In general, an internal combustion engine is an apparatus that operates using energy from heat and pressure generated by burning a gas mixture in a combustion chamber. As an internal combustion engine, a multi-cylinder engine with a plurality of cylinders for increasing power and reducing noise and vibration is generally used.
A diesel engine of the internal combustion engine generally has an efficiency of about 40% in comparison with a gasoline engine, which results from a higher compression ratio of the diesel engine. In addition, devices such as a turbocharger supplying pressurized air to a cylinder and an intercooler cooling an intake air of an engine having a high temperature may be additionally provided to a diesel engine such that an output lower than an output of a gasoline engine in a conventional diesel engine is improved to become equal to or higher than an output of a gasoline engine.
Meanwhile, research for decreasing fuel consumption, and simultaneously increasing an output torque in middle and low speed sections of an engine having a turbocharger has been developed, and research for efficiently controlling to supply a recirculation exhaust gas has been developed.
As one technology according to the research, a cylinder deactivation apparatus of an engine that improves fuel efficiency by deactivating some of a plurality of cylinders in an engine when the engine is driven in middle and low speed sections has been developed
For instance, for a four-cylinder engine, the apparatus may not inject and ignite a gas mixture in two cylinders and may operate the engine with only the other two cylinders.
However, as a capacity of a turbine of a turbocharger is excessive when some of a plurality of cylinders are deactivated, supercharging or turbocharging, efficiency may be decreased, a supply of recirculation exhaust gas may be deteriorated, and thermal efficiency may be decreased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.